PTL 1 discloses a package type fuel cell power generator installed at an indoor site. The fuel cell power generator disclosed in PTL 1 condenses steam, contained in a system exhaust gas discharged from a fuel processing device and a fuel cell main body, to recover the condensed water in a water tank through a drain pipe. PTL 1 describes that water seal is realized by securing a water level in the water tank, so that the condensed water can be prevented from flowing backward to an inside of the main body.